The present invention relates to a ferroelectric material, a ferroelectric film, a method of manufacturing the same, a ferroelectric capacitor, a method of manufacturing the same, a ferroelectric memory, and a piezoelectric device.
A ferroelectric memory is proposed as an 1C memory. The ferroelectric memory includes a ferroelectric film and is formed by placing the ferroelectric film between a pair of electrodes. The ferroelectric memory retains data by spontaneous polarization. As one type of ferroelectric memory, a simple matrix type ferroelectric memory which uses only a ferroelectric capacitor without using a cell transistor is known. The simple matrix type ferroelectric memory has a very simple structure and enables a higher degree of integration. Therefore, development of such a ferroelectric memory has been expected.
The simple matrix type ferroelectric memory has a problem such as occurrence of crosstalk or disturbance, since a voltage one-half to one-third of the operation voltage must be applied to unselected memory cells. In order to prevent occurrence of such a problem, it is a preferable to apply a ferroelectric film with excellent squareness in which the remanent polarization does not occur, or occurs to only a small extent at a coercive voltage or lower and the remanent polarization is saturated at a small voltage at the operating voltage equal to or higher than the coercive voltage.